The broad objective of the proposed research is to identify effective sustainable interventions to dissuade South African adolescents from engaging in behaviors that increase their risk for sexually transmitted diseases (STDs), including HIV. This is a collaborative effort by a multidisciplinary team of researchers from the US and South Africa to implement a clustered randomized trial. The participants will be 1,072 6th- grade South African adolescents at 16 schools in Mdantsane, Eastern Cape Province, South Africa. We will randomly assign the schools to implement a 12-hour HIV Risk-Reduction Intervention adapted from the Be Proud! Be Responsible! curricula found to be effective with Black adolescents in the U.S., or a 12-hour general health promotion intervention concerning health issues unrelated to sexual behavior that will serve as the control condition. Male and female co-facilitators from the community will lead both interventions. The approach draws on social cognitive theory, the theory of reasoned actiodtheory of planned behavior, the applicants? previous HIV/STD risk-reduction research with inner-city African American adolescents, and formative research with members of the study population. The primary outcome measures are the self- reported frequency of unprotected sexual intercourse, sexual intercourse, and condom use. Secondary outcome measures include theoretically relevant variables hypothesized to mediate intervention effects, including intentions, beliefs, and self-efficacy. We will collect data at baseline, immediately postintervention, and at 3-, 6-, and 12-month follow-up. To address the Specific Aims, we will analyze the data with generalized estimating equations (GEE). For instance, we will examine (a) the effects of the interventions on self-reported sexual behavior and mediators of sexual behavior and (b) whether intervention effects are systematically different depending on key moderator variables, including sexual experience, age, gender, intimate-partner violence, and sexual abuse history. The results of this project will contribute to the development of effective sustainable HIV/STD risk-reduction programs for South African adolescents.